package com.lyn.gulimall.product.service.impl;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.lyn.common.utils.PageUtils;
import com.lyn.common.utils.Query;
import com.lyn.gulimall.product.dao.CategoryDao;
import com.lyn.gulimall.product.entity.CategoryEntity;
import com.lyn.gulimall.product.service.CategoryBrandRelationService;
import com.lyn.gulimall.product.service.CategoryService;
import com.lyn.gulimall.product.vo.Catelog2Vo;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.util.StringUtils;

import java.util.*;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;


@Service("categoryService")
public class CategoryServiceImpl extends ServiceImpl<CategoryDao, CategoryEntity> implements CategoryService {
    @Autowired
    CategoryBrandRelationService categoryBrandRelationService;
    @Autowired
    StringRedisTemplate redisTemplate;
    @Autowired
    RedissonClient redissonClient;

    @Override
    public PageUtils queryPage(Map<String, Object> params) {
        IPage<CategoryEntity> page = this.page(
                new Query<CategoryEntity>().getPage(params),
                new QueryWrapper<CategoryEntity>()
        );

        return new PageUtils(page);
    }

    @Override
    public List<CategoryEntity> listWithTree() {
        List<CategoryEntity> entities = baseMapper.selectList(null);
        //一级分类
        List<CategoryEntity> level1Menus = entities.stream().filter((categoryEntity) -> {
            return categoryEntity.getParentCid() == 0;
        }).map((menu)->{
            menu.setChildren(getChildrens(menu,entities));
            return menu;
        }).sorted((menu1,menu2)->{
            return (menu1.getSort()==null?0:menu1.getSort())-(menu2.getSort()==null?0:menu2.getSort());
        }).collect(Collectors.toList());

        return level1Menus;
    }

    @Override
    public void removeMenuByIds(List<Long> asList) {
        //TODO 检查当前删除的菜单，是否被别的地方引用
        baseMapper.deleteBatchIds(asList);
    }

    @Override
    public Long[] findCatelogPath(Long catelogId) {
        List<Long> paths=new ArrayList<>();
        List<Long> parentPath = findParentPath(catelogId, paths);
        Collections.reverse(parentPath);
        return (Long[])parentPath.toArray(new Long[parentPath.size()]);
    }

    /**
     * 级联更新所有关联关系
     * @param category
     */

//    @Caching(evict = {
//            @CacheEvict(value = "category",key = "'getLevel1Categorys'"),
//            @CacheEvict(value = "category",key = "'getCatalogJson'")
//    })
    @CacheEvict(value = "category",allEntries = true)
//    @CachePut
    @Transactional
    @Override
    public void updateCascade(CategoryEntity category) {
        this.updateById(category);
        categoryBrandRelationService.updateCategory(category.getCatId(),category.getName());



        //同时修改缓存中的数据
        //redis.del("catalogJson");等待下次主动查询进行更新

    }

    //每一个需要缓存的数据我们都来指定要放到哪个名字的缓存【缓存的分区（按照业务类型分）】
    @Cacheable(value = "category",key = "#root.method.name",sync = true)    //代表当前方法的结果需要缓存，如果缓存中有，方法不用调用，如果没有，会调用方法，最后将方法的结果放入缓存
    @Override
    public List<CategoryEntity> getLevel1Categorys() {
        List<CategoryEntity> categoryEntities = baseMapper.selectList(new QueryWrapper<CategoryEntity>().
                eq("parent_cid", 0));
        return categoryEntities;
    }

    @Cacheable(value = "category",key = "#root.methodName")
    @Override
    public Map<String, List<Catelog2Vo>> getCatalogJson() {
        System.out.println("查询了数据库…………");
        List<CategoryEntity> selectList = baseMapper.selectList(null);
        //查出所有1级分类
        List<CategoryEntity> level1Categorys = getParent_cid(selectList, 0L);
        //封装数据
        Map<String, List<Catelog2Vo>> parent_cid = level1Categorys.stream().collect(Collectors.toMap(k -> k.getCatId().toString(), v -> {
            //每一个的一级分类，查到这个一级分类的二级分类
            List<CategoryEntity> categoryEntities = getParent_cid(selectList, v.getCatId());
            //封装上面的结果
            List<Catelog2Vo> catelog2Vos = null;
            if (categoryEntities != null) {
                catelog2Vos = categoryEntities.stream().map(l2 -> {
                    Catelog2Vo catelog2Vo = new Catelog2Vo(v.getCatId().toString(),
                            null, l2.getCatId().toString(), l2.getName());

                    //找当前二级分类的三级分类封装成vo
                    List<CategoryEntity> level3Catelog = getParent_cid(selectList, l2.getCatId());

                    if (level3Catelog != null) {
                        List<Catelog2Vo.Catelog3Vo> collect = level3Catelog.stream().map(l3 -> {
                            //封装成指定格式
                            Catelog2Vo.Catelog3Vo catelog3Vo = new Catelog2Vo.Catelog3Vo(l2.getCatId().toString(),
                                    l3.getCatId().toString(), l3.getName());
                            return catelog3Vo;
                        }).collect(Collectors.toList());
                        catelog2Vo.setCatalog3List(collect);
                    }
                    return catelog2Vo;
                }).collect(Collectors.toList());
            }
            return catelog2Vos;
        }));
        return parent_cid;
    }

    //todo 产生堆外内存溢出，OutOfDirectMemoryError
    //1）、springboot2.0以后默认使用lettuce作为redis的客户端，他使用netty进行网络通信
    //2）、lettuce的bug导致netty堆外内存溢出，-Xmx100m：netty如果没有指定堆外内存，默认使用-Xmx100m
    // 可以通过-Dio.netty.maxDirectMemory进行设置
    //解决方案：不能使用-Dio.netty.maxDirectMemory只去调大堆外内存
    //1）、升级lettuce客户端。   2）、切换使用jedis
    //
//    @Override
    public Map<String, List<Catelog2Vo>> getCatalogJson2() {
        //给缓存中放json字符串，拿出的json字符串，还用逆转为能用的对象类型，

        /**
         * 1、空结果缓存，解决缓存穿透
         * 2、设置过期时间（加随机值），解决缓存雪崩
         * 3、加锁，解决缓存击穿
         */

        //加入缓存逻辑，缓存中存的数据是json字符串
        //JSON跨语言，跨平台兼容
        String catalogJson = redisTemplate.opsForValue().get("catalogJson");
        if(StringUtils.isEmpty(catalogJson)){
            //缓存中没有，查询数据库数据
            System.out.println("缓存不命中……将要查询数据库……");
            Map<String, List<Catelog2Vo>> catalogJsonFromDb = getCatalogJsonFromDbWithRedisLock();

            return catalogJsonFromDb;
        }
        System.out.println("缓存命中……直接返回……");
        //转为我们指定的对象
        Map<String, List<Catelog2Vo>> result=JSON.parseObject(catalogJson,new TypeReference<Map<String, List<Catelog2Vo>>>(){});
        return result;
    }

    /**
     * 缓存里面的数据如何和数据库保持一致
     * 缓存数据一致性
     * 1、双写模式
     * 2、失效模式
     * @return
     */
    public Map<String, List<Catelog2Vo>> getCatalogJsonFromDbWithRedissonLock() {
//锁的名字，锁的粒度，越细越快
        //锁的粒度，具体缓存的是某个数据，
        RLock lock = redissonClient.getLock("catalogJson-lock");
        lock.lock();
        //1、占分布式锁。去redis占坑
        Map<String, List<Catelog2Vo>> dataFromDb;
        try {
            dataFromDb = getDataFromDb();
        }finally {
            lock.unlock();
        }
        return dataFromDb;

    }

    public Map<String, List<Catelog2Vo>> getCatalogJsonFromDbWithRedisLock() {

        //1、占分布式锁。去redis占坑
        String uuid = UUID.randomUUID().toString();
        Boolean lock = redisTemplate.opsForValue().setIfAbsent("lock", uuid,300,TimeUnit.SECONDS);
        if(lock){
            System.out.println("获取分布式锁成功……");
            //加锁成功执行业务
            //设置过期时间，必须和加锁同步
//            redisTemplate.expire("lock",30,TimeUnit.SECONDS);
            Map<String, List<Catelog2Vo>> dataFromDb;
            try {
                dataFromDb = getDataFromDb();
            }finally {
                String script = "if redis.call('get', KEYS[1])== ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end";
                //删除锁
                Long lock1 = redisTemplate.execute(new DefaultRedisScript<Long>(script, Long.class), Arrays.asList("lock"), uuid);
            }
//            redisTemplate.delete("lock");
//            String lockValue = redisTemplate.opsForValue().get("lock");
//            if(uuid.equals(lockValue)){
//                redisTemplate.delete("lock");
//            }
            return dataFromDb;
        }else{
            //加锁失败重试
            System.out.println("获取分布式锁失败……等待重试");
            try {
                Thread.sleep(200);
            }catch (Exception e){

            }
            return getCatalogJsonFromDbWithRedisLock();
        }

    }

    private Map<String, List<Catelog2Vo>> getDataFromDb() {
        String catalogJson = redisTemplate.opsForValue().get("catalogJson");
        if (!StringUtils.isEmpty(catalogJson)) {
            //缓存不为null直接返回
            Map<String, List<Catelog2Vo>> result = JSON.parseObject(catalogJson, new TypeReference<Map<String, List<Catelog2Vo>>>() {
            });
            return result;
        }
        System.out.println("查询了数据库…………");

        List<CategoryEntity> selectList = baseMapper.selectList(null);

        //查出所有1级分类
        List<CategoryEntity> level1Categorys = getParent_cid(selectList, 0L);

        //封装数据
        Map<String, List<Catelog2Vo>> parent_cid = level1Categorys.stream().collect(Collectors.toMap(k -> k.getCatId().toString(), v -> {
            //每一个的一级分类，查到这个一级分类的二级分类
            List<CategoryEntity> categoryEntities = getParent_cid(selectList, v.getCatId());
            //封装上面的结果
            List<Catelog2Vo> catelog2Vos = null;
            if (categoryEntities != null) {
                catelog2Vos = categoryEntities.stream().map(l2 -> {
                    Catelog2Vo catelog2Vo = new Catelog2Vo(v.getCatId().toString(),
                            null, l2.getCatId().toString(), l2.getName());

                    //找当前二级分类的三级分类封装成vo
                    List<CategoryEntity> level3Catelog = getParent_cid(selectList, l2.getCatId());

                    if (level3Catelog != null) {
                        List<Catelog2Vo.Catelog3Vo> collect = level3Catelog.stream().map(l3 -> {
                            //封装成指定格式
                            Catelog2Vo.Catelog3Vo catelog3Vo = new Catelog2Vo.Catelog3Vo(l2.getCatId().toString(),
                                    l3.getCatId().toString(), l3.getName());
                            return catelog3Vo;
                        }).collect(Collectors.toList());
                        catelog2Vo.setCatalog3List(collect);
                    }
                    return catelog2Vo;
                }).collect(Collectors.toList());
            }
            return catelog2Vos;
        }));
        //查到的数据再放入缓存
        String s = JSON.toJSONString(parent_cid);
        redisTemplate.opsForValue().set("catalogJson", s, 1, TimeUnit.DAYS);
        return parent_cid;
    }

    //从数据库查询并封装分类数据
    public Map<String, List<Catelog2Vo>> getCatalogJsonFromDbWithLocalLock() {

        //只要是1同一把锁，就能锁住需要这个锁的所有线程
        //1、synchronized (this)，springboot所有的组件在容器中都是单例的
        //todo 本地锁，synchronized,JUC(Lock),在分布式情况下，想要锁住所有，必须使用分布式锁

        synchronized (this) {
            //得到锁以后，我们应该再去缓存中确定一次，如果没有才需要继续查询
            return getDataFromDb();
        }
    }

    private List<CategoryEntity> getParent_cid(List<CategoryEntity> selectList,Long parent_cid) {
        List<CategoryEntity> collect = selectList.stream().filter(item -> {
            return item.getParentCid() == parent_cid;
        }).collect(Collectors.toList());
        return collect;
//        return baseMapper.selectList(new QueryWrapper<CategoryEntity>().eq("parent_cid", v.getCatId()));
    }

    private List<Long> findParentPath(Long catelogId,List<Long> paths){
        paths.add(catelogId);
        CategoryEntity byId=this.getById(catelogId);
        if(byId.getParentCid()!=0){
            findParentPath(byId.getParentCid(),paths);
        }
        return paths;
    }

    //递归查找所有菜单的子菜单
    private List<CategoryEntity> getChildrens(CategoryEntity root,List<CategoryEntity> all){
        List<CategoryEntity> children = all.stream().filter(categoryEntity -> {
            return categoryEntity.getParentCid().equals(root.getCatId());
        }).map(categoryEntity -> {
            //找到子菜单
            categoryEntity.setChildren(getChildrens(categoryEntity,all));
            return categoryEntity;
        }).sorted((menu1,menu2)->{
            //菜单的排序
            return (menu1.getSort()==null?0:menu1.getSort())-(menu2.getSort()==null?0:menu2.getSort());
        }).collect(Collectors.toList());
        return children;
    }

}